private void btnTPTranChauQQ_Click(object sender, EventArgs e) { DataTable dt = data.dataReaderTable("select DonGiaMon from Mon where TenMon = N'" + btnTPTranChauQQ.Text + "'"); int dongia = Convert.ToInt32(dt.Rows[0]["DonGiaMon"].ToString()); int soluong = 1; float giamgia = 0; string ghichu = ""; string time = DateTime.Now.ToString(); string MaMon = ""; away.addMon(++away.stt, btnTPTranChauQQ.Text, soluong, giamgia, dongia, ghichu, time, soluong * dongia - (soluong * dongia * giamgia), MaMon); }